For more than a year after Easter Monday, 1865, Collis worked on the railroad with an intensity that frightened even Leland. Although Charles was officially in charge of construction, Collis would visit the railhead two or three times a week, pale-faced, dark-eyed, in his tall black silk hat and his black tailcoat. He was so sharp and emaciated these days that the Irish labourers called him the Raven, and the Chinese called him Yama, after the thin and elegant oriental demon who presided over Pitris, or hell.

The first challenge to Collis’s freshly-fired obsession with completing the railroad came fifty-seven miles out of Sacramento, where the graders were confronted with a huge bulk of shale, protruding out of the slope of the Sierras nearly two thousand feet above the foaming cleft of the American River. It was here that Collis and Theodore and Wang-Pu had stopped with Doc Kates to share a picnic lunch; but to the railroad engineers, the outcropping looked so forbidding and impassable that they quickly christened it Cape Horn. It fell at an angle of seventy-five degrees straight down to the river gorge, and yet somehow they were supposed to cut a ledge into it to carry a railroad.

Collis went to inspect it on a windy afternoon, with Charles plodding silently beside him. Kwang Lee came too, a few steps behind Collis, dressed in a very long brown tweed overcoat.

‘This is typical of Theodore,’ said Charles, pointing out Cape Horn on the survey map. ‘He was always seeing soft digging dirt where there was nothing but solid rock.’

Collis lifted his eyes towards the summit of the outcropping. It was grey, and rugged, and sparsely scattered with trees. From close up, it looked like one of the shoulders of the world.

‘You need to blast, right?’ Collis asked Charles.

Charles nodded. ‘The trouble is, how are we going to get a blasting crew to perch on a seventy-five-degree slope while they bore the holes for the charges?’

Collis thought for a while, and then beckoned Kwang Lee forward. ‘This is just an idea,’ he said. ‘Supposing the Chinese climbed to the top of the rocks and built winches up there. Then supposing they were lowered in baskets down the face of the shale, so that they could drill anywhere they liked. Do you think they’d do it?’

Charles raised an eyebrow. But Kwang Lee took a careful look at Cape Horn and then said, ‘I think they would find great pride in blasting that rock, Mr Edmonds. Do you want me to pass the instructions on?’

‘I’d be grateful,’ said Collis.

Charles watched the Chinaman go and then said, ‘Well, I’ll be damned.’

During the following weeks, Chinese workers were winched down the rocky spur until they were dangling fourteen hundred feet above the American River. With hand drills, sledgehammers, and barrels of black gunpowder, they gradually blasted a ledge across the uncompromising spur, until they reached the far side.